Armond P A, Schreiber U, Björkman O
Department of Plant Biology, Carnegie Institution of Washington, Stanford, California 94305.
Plant Physiol. 1978 Mar;61(3):411-5. doi: 10.1104/pp.61.3.411.
The response of photosynthetic electron transport and light-harvesting efficiency to high temperatures was studied in the desert shrub Larrea divaricata Cav. Plants were grown at day/night temperatures of 20/15, 32/25, or 45/33 C in rough approximation of natural seasonal temperature variations. The process of acclimation to high temperatures involves an enhancement of the stability of the interactions between the light-harvesting pigments and the photosystem reaction centers. As temperature is increased, the heat-induced dissociation of these complexes results in a decrease in the quantum yield of electron transport at limiting light intensity, followed by a loss of electron transport activity at rate-saturating light intensity. The decreased quantum yield can be attributed to a block of excitation energy transfer from chlorophyll b to chlorophyll a, and changes in the distribution of the excitation energy between photosystems II and I. The block of excitation energy transfer is characterized by a loss of the effectiveness of 480 nm light (absorbed primarily by chlorophyll b) to drive protochemical processes, as well as fluorescence emission by chlorophyll b.
研究了沙漠灌木白花丹（Larrea divaricata Cav.）光合电子传递和光能捕获效率对高温的响应。植株在白天/夜间温度分别为20/15、32/25或45/33℃的条件下生长，大致模拟自然季节温度变化。高温适应过程涉及增强光能捕获色素与光系统反应中心之间相互作用的稳定性。随着温度升高，这些复合物的热诱导解离导致在限制光强下电子传递的量子产率降低，随后在光强饱和时电子传递活性丧失。量子产率降低可归因于从叶绿素b到叶绿素a的激发能传递受阻，以及光系统II和I之间激发能分布的变化。激发能传递受阻的特征是480nm光（主要由叶绿素b吸收）驱动原化学过程的有效性丧失，以及叶绿素b的荧光发射。
